Process for forming a slub yarn



' J 1964 J. L. EDWARDS ETAL 3,116,589

PROCESS FOR FORMING A SLUB YARN Filed Dec. 21, 1961 INVENTORS JAMES L. EDWARDS EDGAR I. RHODEN PAUL T. SCOTT BY wimmf ATTORNEY United States Patent 3,116,589 PROCESS FOR FORMING A SLUB YARN James L. Edwards, Kinsto'n, N.C., Edgar I. Rhoden,

Newark, Del., and Paul T. Scott, Kinston, N.C.,

assignors to E. I. du Pont'de Nemours and Company,

Wilmington, DeL, a corporation of Delaware Filed Dec. 21, 1961, Ser. No. 161,221 7 Claims. (Cl. 57-'-157) This invention relates to fluid treatment of yarn to introduce slubs or intermittent portions of greater denier than the remainder of the yarn.

Fluid treatment of yarn to impart bulkiness has become well known in the art. Flu-id jets are used to introduce coils, loops and whorlsrandomly along the yarn filaments as described in Breen U.S. Patents No. 2,783,- 609, No. 2,852,906, and No. 2,869,967. Such treatments are particularly concerned with providing as uniformly bulked or textured yarn as possible, since uniform yarns are generally the most important article of commerce in the textile industry. However, the effectiveness of the texturizing treatment or bulking action can be made nonuniform along the yarn as described in U.S. Patents to Griset, No. 2,874,444, and to Field, No. 2,931,090. The novelty yarn produced in this way has a predominance of untextured portions which have been substantially unaffected by the treatment and intermittent bulked portions, which are either in the form of relatively short nubs or longer conventionally texturized portions, but are not of sufficient size to qualify as slubs.

It is sometimes desirable to produce yarns having much more decided variations in texture and denier in order to obtain novelty effects in fabrics for such purposes as casement fabrics, draperies, dress goods, upholstery fabrics and the like. Slub yarn for such purposes has been obtained in the form of silk threads from imperfect, freak or double cocoons, or from cocoons of wild or uncultivated silk worms. These doupioni silks are irregular in texture and carry slubs or thickened portions at irregular intervals. They are in limited supply. Methods for producing similar yarn synthetically have involved varying extrusion conditions so that the individual filaments vary considerably in denier or the filaments are caused to pile up and coalesce or stick together. The product has a harsh hand and less desirable appearance than doupioni ilk, and is expensive to produce because of the low production rate and special process conditions required.

It is an object of the present invention to provide an improved method for producing a slub yarn. A further object is to providea novel slub yarn in which the slubs are formed of entangled continuous filaments and are stable even though the filaments are not coalesced or otherwise stuck together. Other objects will become apparent from the disclosure and claims.

The process of this invention is suitable for forming stable slubs in any conventional organic textile yarn composed wholly or in part of continuous filaments. The yarn is continuously fed to a supply jet and forwarded by the jet in a high velocity stream of compressible'fiuid to impinge at an angle against a foraminous surface, preferably a screen. The essential function of this jet is to open up the yarn bundle and distribute the filaments in random fashion on the surface, and jets of the type disclosed in the above-mentioned patents are suitable for this purpose, but the jet may also be operated so as to'bulk, crimp or otherwise texturize the yarn.

Slubs are formed in the yarn by means of a second jet. This slubbing jet directs a high velocity stream of compressible fluid against the foraminous surface adjacent to and at a converging angle to the stream from the supply jet. This creates a zone of turbulence between the streams 3,116,589 Fatented Jan. 7, 1954 which causes filaments of the open yarn bundle'to fold back on themselves, initiating the formation of slubs. The yarn is then withdrawn from the'surface at a rate of at least 5% less-than the feed rate to retain the folds in the yarn. The folds or filament loops are consolidated in the yarn as slubs'by withdrawing the yarn through the slub jet stream in a direction which is counter-current to the flowing stream. The turbulent flow causes the filaments to intermingle and entagle the folds or loops to form stable slubs which are random in length and distribution.

The jets disclosed in the above-mentioned patents are also suitable for use as slubbing jets. However, it may be preferable to use interlacing jets of the type disclosed in Bunting and Nelson U.S. Patent No. 2,985,995, arranged so as to provide a stream of fluid counter-current to the direction of yarn travel to the jet from the screen for the required slubbing action. Then, as the yarn passes through the jet, the filaments are separated and interlaced to hold the slubs firmly in place.

The slubs can be further consolidated in the yarn by adding a third jet, after the slubbing jet, to twist protruding loops or ends about the yarn. Torque jets of the type disclosed in Breen and Sussrnan U.S. Patent No. 2,997,837 and also No. 3,069,309 are suitable for this purpose. A torque jet can be used as the sluboing jet to combine these operations, thereby providing economy in fluid consumption. This has the unexpected result of improving the operability of the slubbing process. When poor weavability results from weak spots in the yarn within slubbed regions, it is particularly advantageous to use the torque jet to ply the slubbed yarn with an unslubbed carrier yarn.

In the drawing, which illustrates the invention discussed hereinafter,

FIGURE 1 is a diagrammatic representation of one embodiment of the process and the apparatus used therein, and

FIGURE 2 is an enlarged view of one form of slub yarn product of the invention.

Referring to the drawing, substantially Zero twist multifilament yarn 1 is withdrawn from supply package 2 through pigtail guide 3, tension gate 4 and guide 5 by feed rolls 6 and 7, the yarn passing a sufficient number of times around the pair of rolls to provide positive control of the feed rate. The yarn then passes through supply jet 8 and is forwarded to screen 10 by air introduced into the jet through fitting 9 to form a high velocity stream. The yarn is struck against the screen at an oblique angle of about 45 by air passing through the screen. A slub jet 11, similar to the supply jet, is supplied with air under pressure through fitting 12 to form a high velocity stream which is directed perpendicularly against the screen to impinge on the screen adjacent to the other stream from the supply jet. The turbulence created between the two streams causes the yarn totwist, loop and entangle on itself. The yarn is withdrawn from the screen through the slub jet and over pigtail guide 13 by take-up rolls .14 and 15 similar to feed rolls 6 and 7, but operated at a slower speed. As the yarn is pulled through the slub jet, the slubs are firmly consolidated in the yarn by interiningling of the folds, loops and filaments of the slubs and base yarn bundle. The slub yarn passes from the take-up roll 14 to a conventional windup, such as a package 1 6 surface driven by a roll 17.

Suitable process conditions are illustrated in the examples of Table I. The general procedure described above is followed with the specific operating details indicated for each example. Under the heading, Yarn Treated, 70/ 50/ 0 indicates a 70 denier yarn of 50 filaments and Zero twist. The angles given in the last column refer to the angle at which the supply jet fluid is directed against the screen. This angle may be from substantially to 90 and in Example 19 is varied over the entire range. The process is likewise operable with slub jet angles over this broad range although the examples illustrate operation with the slub jet arranged to direct fluid perpendicular to the screen as shown in the drawing. Example 20 illustrates the use of a torque jet to ply slubbed yarn with an unslubbed carrier yarn for greater strength.

The characteristics of novel slub yarn products obtained are shown in Table II for typical examples of Table I. The products are entirely random in appearance with slubs in a wide range of lengths, thicknesses and frequencies. The corresponding random location of slubs in fabric woven from the yarn is a distinct advantage. However, the special procedure of Example 19 can give suificient regularity to provide a novel stripe effect in fabric woven from this particular type of slub yarn.

un1n2O of US. Patent No. 2,985,995. The base yarn of these new slub yarns has a coherency factor of at least and the slub portion has a coherency factor of at least 20% greater than the base yarn. Thus the ratio of the coherency factor of slub portions to that of the base yarn is at least 1.211. Base yarn coherency factors are frequently greater than the 60 to 90 shown in Table II and can run as high as 200400. The slub coherency factor will usually be 100-300 and can run as high as 400-900. With the process conditions of Example 11 a slub yarn is obtained which has a base yarn coherency factor of about 240 and a slub coherency factor of about 370. The corresponding values for Example 12 are about 300 and 400, respectively.

One of the major variables for controlling product characteristics is the overfeed, i.e., the rate at which the yarn is fed to the supply jet versus the rate at which it is withdrawn from the slubbing jet. The range can be varied within wide limits primarily to change slub size Table I.Examples of Process Conditions Yzarn Spe)e(l Supply J et Slub Jet (Distances in Inches) y. .m. Exlample Yarn Treated p Feed Wind Pressure Temp. Pressure Temp. Supply Slub Jet Scp- Jet 00- Angle of Rate up (p.s.i.g.) C.) (p.s.i.g.) 0.) Jet to Jet to aratiou Set Supply Screen Screen Jet, de-

grees 1 70/50/0 polyethylene tereph- 950 830 10-12 150 40 20 2% 2 2 0 /1 45 t in a e. 2 do. 950 830 10-12 255 40 20 2% 2% 6 A 45 3 (lo 950 600 5 20 40 250 3 5 3 5 5% 0 50 4 70/50/0 pol rylene tereph- 950 723 5 20 40 225 3%; 3 54s 5% 0 50 thalate Trilobal. 5 70/50/51 polyethylene tcreph- 950 633 5 20 40 290 3 5 3 340 5 O 50 t in a e.

950 803 3-5 20 40 20 2 540 1% 5% 0 45 950 803 3-5 20 40 20 2 7s 1% 5% A 45 0.. 950 803 3-5 20 40 20 2 l E 1 u 1 2 5A 1 45 300/150/0 polyethylene tcr' 950 783 20 20 100 20 2% 2 5 A 43 ephthalate. 200/100/0 polyethylene ter- 950 783 14-15 20 60 20 2% 2 5 ,5 43

ephthalate. 100/50/0 polyethylene ter- 950 783 14-15 20 80 20 2% 2 5 A 43 ephthalate. 70/50/10 potlyethylenc tcreph- 2700 2410 -35 20 100 20 4 1% 8 0 45 t a a e. 1000/200/0 polyethylene ter- 933 836 30 20 100 20 4 2 0 0 55 ephthalate. 150/40/0 cellulose acetate 933 700 7 20 40 20 2% 1 /3 4% as 42 100/34/0 06 nylon.. 933 760 7-10 20 80 20 2 4 1% 4% /4 200/80/0 acrylic fiber. 933 766 20 20 80 20 2A 114 4% as 42 100/60/0 dull viscose 933 760 10-12 20 30 20 2 /4 1% 4% ")4; 42 100/68/0 polyethylene ter- 050 703 5-10 20 30 20 2 ,4 1A 5 ,4 00

ephthalate. do 950 703 5-10 20 30 20 2A 2% 5 ,1; 1 00-0 70/5h0/0 polyethylene tereph- 900 750 6 20 60 20 254 1% 4% 0 9 t ala e. 21 do 950 836 3-5 20 20 2% 1% 5% 0 1 Jet is pivoted regularly toward and away from the slub jet at one swing per five seconds in Example 19.

3 In Example 20 a 40/27/0 carrier yarn of polyethylene combined yarns are passed from the slub jet through a torque jet Table II.-Clzaraclerizati0n Parameters of Various Slub Yarns Slub Characterization Ex. 4 Ex. 8 Ex. 9 Ex. Ex. EX. Ex.

Parameters 16 18 20 21 Avg. Slub Length inches. 2. 2 2. 0 11. 1 9.0 21. 8 11. 5 l. 23 Avg. Slub Length, Std.

11. of Variation Percent. 131 109 104 157 133 105 130 slubs/100 Yds 43 74 11 15 11 15 119 Avg. Denier Ratio of Slub to Base Yarn 5. 5 5.5 3.5 5.5 3.3 4.0 4.0 Percent of Slubs Having a Length Greater than (a) Avg. Length. 18 19 24 28 33 (b) 2 X Avg. Length. 13 12 15 12 10 (c) 7 x Avg. Length 3 4 1. 8 4.0 0.7 (d) 1 inch 57 54. 2 80. 3 50. 7 30. 5 (e) 5 inches.. 33 34. G 57. 5 34. 7 2. 5 (1') 10 inches 40 25.0 0 Longest Slub in Samples Analyzed, inches 24 18 111 S0 176 126 0 Base Yarn Coherency Factor 82 77 03 Slub Coherency Faetor 101 130 102 The coherency factor given in Table I1 is determined by the hook-drop test described in detail starting in colterephthalate is fed separately at 750 yards per minute to the entrance of the slub jet and the supplied with 60 p.s.i.g. air at 20C.

and frequency. Generally speaking, this overfeed can vary from 5-200% or more. A great many useful yarns can be prepared between the overfeed ranges of 670%, while a preferred range for some of the most interesting yarns is from 850%. As used herein, overfeed is defined as:

Feed rate wrthdrawal1ate X Withdrawal rate It will be obvious that two or more yarns can be passed to the supply jet at the same or different rates of speed. Simultaneous, but individually random, slubbing of two ends to produce a plied yarn has unexpectedly overcome certain weaving problems. It is further obvious that the feed rate to the supply jet may be constant or varied. As another variation, one or more yarns of the same or different nature may be added immediately prior to the slubbing jet, e.g., at or through the foraminous surface. The composite yarn will then pass through the slubbing jet to the windup. Thus, a carrier-effect yarn may be obtained which is useful for specialized applications. This is particularly useful for plying slub yarn with a carrier yarn to strengthen any weak spots which would cause difiiculty in weaving.

Overfeed= Any synthetic or natural fiber yarns can be used to make the novel products described previously. Suitable materials include all the fiber-forming polyamides such as 6 nylon, 66 nylon, 610 nylon. The polyester yarns are all useful and include polyesters of terephthalic acid or isophthalic acid and a lower glycol, e.g., poly(ethylene terephthalate), poly(hexahydro-p-xylylene terephthal ate). Another subclass of these general chemical classes are the spontaneously elongatable yarns-these are particularly interesting for novelty effects in the lower ranges of overfeed and especially if a heated fluid is used in the supply jet and/or the slubbing jet. Other conventional classes of fiber-forming materials include regenerated cellulose, the cellulose esters, and the acrylic, vinyl, and vinylidene polymers, as well as the many suitable fiber-forming copolymers of any of these groups. The natural fibers, such as cotton, wool, linen or silk, can be used alone or in com bination.

Preferably, the yarn to be treated is a continuous multifilament yarn and at zero twist. Obviously, it is more economical to use a feed yarn in the twist-free state rather than putting it through an auxiliary untwisting operation. It may be desirable, however, for special effects or specific end uses to use a pretwisted yarn or, perhaps, to add a pretwisted yarn as a carrier yarn after the supply jet but prior to the slubbing jet. This process actually interlaces both the carrier yarn and the slub portion so that posttwisting is unnecessary. The yarn bundle and the slub have a high degree of coherency so that they are suitable as is for further textile pnocessing. Here again, however, it is entirely possible to post-twist the slub yarns either to ply with some other material or to twist to some specific level fora specific end use.

Other suitable feed yarns include a sliver or roving of staple fibers. In such cases, the supply jet will prefer-ably be an interlacing jet or a torque jet which, in addition to forwarding the yarn bundle, will provide adequate mapping and/ or intermingling of the filaments and the freefiber ends to achieve a coherent staple yarn.

The feed yarns can also include monofils or twistlively yarns. These are diflicult to handle and slub effectively, but they can be included for unusual results.

Almost any jet is suitable to slub the yarn provided that the fluid flow is counter-current to the yarn movement tension to the yarn bundle. The slubbing jet also intermingles and interlaces the slub land the base yarn and has a large enough diameter to allow the slub portion to pas through. It is not essential but a jet fluid flow pattern that induces a twisting action is advantageous to wrapping in the slub components. Other jets similar to those described under the section on supply jets can be used to slub the yarn. I

Torque jets are a preferred species of slubbing jet. An interesting variation is adding a torque jet immediately after the slubbing jet. For economy of fluid consumption, however, it is preferred to combine the slubbing jet with the torqueing effect desired. Suitable types of torque jets are described in U.S. Patent No. 3,009,309.

The fluid used in either jet may be heated, at room temperature, or refrigerated. Suitable compressible fluids include air, steam, gases, vapors, and the like, to twist, intermingle loop, slub or forward the yarn. Heat, water vapor, or other plasticizing means may :be used if it is desired to plasticize the yarn so that crimping, relaxation or permanent filament twist results. The only upper limit to the treating temperature is the yarn melting or degradation point. The sa-lvogenic action of solvent vapors or other plasticizers should be adjusted so that the continuity of the yarn bundle is maintained.

Obviously, the type, temperature, and pressure of fluid can be varied over a very wide range. The fluid conditions in each jet may be the same or different depending upon the characteristics of the slub yarn product desired. Thus, one can greatly augment the types of novelty yarns by this new process. The supply jet normally interlaces the yarn to a certain extent, but at the same time, it can be used to precrimp the yarn by the process described in Belgian Patent No. 573,230, or to make loopy yarn as described in U.S. Patent No. 2,783,609.

The fluid flow in either or both jets can be adjusted and/ or the yarn may be selected so that the fluid turbulence breaks-some of the filaments. This gives loopy slub yarns with free-fiber ends analogous to some of the products produced in US. Patent No. 2,869,967.

The process can be operated at very high yarn speeds of the order of 3000 or more yards/ minute. Conventional textile processing speeds of 200-2000 yards/minute are easily obtained, and a preferred range for some types of slub yarns is from 4004000 yards/minute. The only real upper limit to processing speeds is the rate at which the yarn can be accurately metered to the supply jet and the rate at which the yarn can be wound up onto a suitable backwindable package.

This process produces a whole new family of completely random slub yarns. The random nature avoids any periodicity with resultant unsightly, geometric patterns in the fabric prepared from such yarns. Since the process is capable of being operated at very high speeds, it can be easily coupled to the spinning and/or drawing operations of conventional synthetic yarns without the need for an intermediate packaging operation.

Since many diiferent embodiments of the invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited by the specific illustrations except to the extent defined in the following claims.

We claim:

1. The process for forming slubs in a yarn which comprises continuously feeding the yarn to a supply jet, forwarding the yarn through the jet with a high velocity stream of compressible fluid, forwarding .the yarn in the stream to impinge against a forminous surface at an angle, continuously withdrawing the yarn from the surface at a rate at least 5% less than the rate of feed, directing a second high velocity stream of compressible fluid from a slubbing jet against the foraminous surface so that the yarn passes through the stream in a countercurrent direction to produce slubs composed of yarn loops consolidated into the yarn by filament entanglement, and collecting the slub yarn.

2. A process as defined in claim 1 wherein said slubbing jet is an interlacing jet and the yarn is withdrawn from the surface through said jet to stabilize the slub configuration by interlacing the yarn filaments.

3. A process defined in claim 1 wherein said slubbing jet is a torque jet and the yarn is withdrawn from the surface through said jet to twist consolidate the slub yarn.

4. The process for forming slubs in a yarn which comprises jetting two converging high velocity streams of compressible fluid against a foraminous surface at adjacent points to form a zone of turbulence between the streams, continuously feeding yarn to one of said streams and forwarding the yarn concurrently with the flowing fluid to the surf-ace, continuously withdrawing the yarn from the surface through the other stream counter-currently to the flowing fluid at a rate at least 5% less than the yarn feed rate to form loops in the yarn during passage through the zone of turbulence between the streams and to consolidate the loops into the yarn as stable slubs during passage through the counter-current stream, and collecting the resulting slub yarn.

5. A process as defined in claim 4 wherein the countercurrent stream includes at least one fluid vortex having a steep velocity gradient which separates and intermingles the yarn filaments to provide a stable interlaced slub yarn.

6. A process as defined in claim 5 wherein two yarns are fed to the surface and combined into a single slub yarn.

7. The process for forming slub yarn which comprises forming loops in a yarn by continuously forwarding the yarn onto a foraminous surface at a high rate of feed and withdrawing the yarn at a slower rate providing a 5% to 200% overfeed to the surface, and consolidating the loops into the yarn as stable slubs by withdrawing the yarn through a counter-current stream of compressible fluid jetted at high velocity against the yarn on the foraininous surface.

References Cited in the file of this patent UNITED STATES PATENTS 2,435,891 Lodge Feb. 10, 1948 8 Breen Mar. 5, 1957 Griset Oct, 1, 1957 Breen Jan. 20, 1959 Field Apr. 5, 1960 Breen Dec. 19, 1961 Breen Jan. 23, 1962 Cook et a1 May 29, 1962 Claussen et al Sept. 25, 1962 FOREIGN PATENTS France Feb. 15, 1960 Great Britain June 5, 1957 

1. THE PROCESS FOR FORMING SLUBS IN A YARD WHICH COMPRISED CONTINUOUSLY FEEDING THE YARN TO A SUPPLY JET, FORWARDING THE YARN THROUGH THE JET WHICH A HIGH VELOCITY STEAM OF COMPRESSIBLE FLUID, FORWARDING THE YARN IN THE STEAM TO IMPINGE AGAINST A FORMINOUS SURFACE AT AN ANGLE, CONTINUOUSLY WITHDRAWING THE YARN FROM THE SURFACE AT A RATE OF LEAST 5% LESS THAN THE RATE OF FEED, DIRECTING A SECOND HIGH VELOCITY STREAM OF COMPRESSIBLE FLUID FROM A SLUBBING JET AGAINST THE FORAMINOUS SURFACE SO THAT THE YARN PASSES THROUGH THE STREAM IN A COUNTERCURRENT DIRECTION TO PRODUCE SLUBS COMPOSED OF YARN LOOPS CONSOLIDATED INTO THE YARN BY FILAMENT ENTANGLEMENT, AND COLLECTING THE SLUB YARN. 